1. Technical Field
The present disclosure relates to an industrial robot including an encoder and a power supply for the encoder.
2. Background Art
An industrial robot includes a manipulator, a control device for controlling an operation of the manipulator, and a connection cable connecting the manipulator to the control device. Noise in the connection cable due to extension of the connection cable presents a problem.
Generally, a conventional industrial robot is configured as shown in FIG. 3. The configuration is hereinafter described with reference to FIG. 3.
As shown in FIG. 3, industrial robot 101 includes control device 102, manipulator 103, a plurality of motors 104, a plurality of encoders 105, and connection cable 106. Motors 104 drive manipulator 103. Each encoder 105 is attached on each motor 104, and detects rotation position, angle, or speed of each motor 104. Connection cable 106 transmits, to control device 102, feedback signals output from the plurality of encoders 105.
FIG. 3 shows only components related to the present disclosure (described later). FIG. 3 shows six-axis manipulator 103, for example.
Control device 102 and manipulator 103 are interconnected via connection cable 106, and signals or information can be communicated between them. For example, electric power for encoders 105 is supplied and a driving command is transmitted from control device 102 to manipulator 103. A signal or the like related to information of each joint (axis) of manipulator 103 that has been detected by encoders 105 is transmitted from manipulator 103 to control device 102.
In conventional industrial robot 101, power supply sections 107 for encoders 105 are disposed near encoders 105 attached on motors 104 constituting manipulator 103. This configuration solves problems arising when connection cable 106 is long, for example voltage drop and noise by connection cable 106 (for example, Unexamined Japanese Patent Publication No. H10-006273).
Each power supply section 107 is formed of a printed board, and the printed board includes a constant voltage element and a filter. The constant voltage element is a power source for encoder 105, and outputs fluctuating input voltage as a constant voltage. The filter removes noise occurring between control device 102 and power supply section 107.
By disposing power supply section 107 as a printed board near encoder 105, the filter disposed in the printed board can remove noise immediately before electric power is input into encoder 105. Therefore, encoder 105 is not affected by noise occurring in connection cable 106 that connects control device 102 to manipulator 103.
The voltage drop by connection cable 106 is allowed within the fluctuation range of the input voltage of the constant voltage element. Therefore, connection cable 106 can be elongated.
In the conventional industrial robot, a battery that supplies electric power to encoder 105 when control device 102 stops and hence power supply from power supply section 107 to encoder 105 stops is disposed near power supply section 107. The battery is a standby power source used when encoder 105 stores rotation position information or the like of motor 104.